The present invention relates generally to a pulsimeter, and more particularly to a pulsimeter having a protective circuit for preventing destruction of the pulse detection circuit by static electricity.
Electrocardiography is one of the conventional pulse counting methods. This is the method of detecting minute electric signals from the heart generated before contraction of the heart. The electrocardiography is characterized by the following features:
(1) Simple and highly reliable. Heartbeats can be counted only by touching two metal electrodes with both hands or fingers.
(2) Suitable for miniature devices exhibiting long life. Electric signals from the heart can be detected with minute power (about 100 uW).
A portable miniature pulsimeter can be manufactured using the electrocardiography method. In the conventional circuit and electrode structure, however, the elements of the circuit input portion connected to the electrode may sometimes be destroyed by the electric discharge of static electricity at an instant the person or clothes touches the detection electrode. As a result the pulsimeter may lose the pulse detecting and counting functions.